Adult neurogenesis is decreased in the olfactory bulb of the cerebral hemisphere ipsilateral to CCI. (a) Long-term BrdU incorporation analysis identifies olfactory bulb interneurons generated from adult neural stem cells in the SVZ of adult mice. Sagittal sections processed for anti-BrdU IHC at 30 days post-procedure following BrdU at 0, 24, 48 and 72 hours post-procedure. BrdU + cells are distributed in the granular cell layer (gr) and glomerular layer (gl) of the olfactory bulb (OB) and rostral migratory stream (RMS) passing between the cortex (Cex) and striatum (Str). Scale bar = 200 μm. (b) Higher magnification images from sagittal sections of the olfactory bulb ipsilateral to the CCI or sham craniotomy. Dual anti-BrdU/anti-NeuN immunolabeled neurons (arrows) in the olfactory bulb granular cell layer consistent with BrdU-incorporation in olfactory bulb-fated SVZ neural stem cells. Scale bar = 20 μm. (c) Stereological cell counts reveal a significant decrease in the numbers of BrdU-incorporated, NeuN immunopositive neurons in the granular cell layer in the olfactory bulb ipsilateral to moderate and mild CCI at 30 days post-injury (*** p < 0.001 moderate CCI versus naïve, ** p < 0.01 mild CCI versus naïve [n = 4/group], one-way ANOVA with Tukey’s multiple comparison post test). (d) Cell counts reveal an increase in BrdU-incorporated cells in the neocortex ipsilateral to moderate and mild CCI at 30 days post procedure (* p < 0.05 versus naïve [n = 5/group], one-way ANOVA with Tukey’s multiple comparison post test). (e) BrdU + cells in the injured cortex do not express NeuN. Scale bar = 20 μm. (f) Triple anti-BrdU/anti-GFAP/anti-Iba1 IHC reveals dual BrdU + /GFAP + cells (arrows). Scale bar = 20 μm (g) Quantification confirms many BrdU-incorporated cells have acquired a GFAP + astrocytic fate in the injured cortex 30 days post-injury.